The LiNbO3-LN or (Pb,La)(Zr,Ti)O3-PLZT or waveguide-based optical switch is commercially available. The LN/PLZT waveguide-based optical switch is a modified balance bridge type 1×2 switch, which is composed of (a) a Mach-Zehnder (MZ) device integrated with top electrodes and (b) input-output 3-dB couplers.
The switching speed of an LN waveguide-based optical switch is approximately 100 nanoseconds. Furthermore, it suffers from (a) high voltage requirements, (b) polarization dependence problems and (c) DC drift.
The switching speed of a PLZT waveguide-based optical switch is approximately 10 nanoseconds.
The switching speed of a semiconductor optical amplifier (SOA) waveguide-based optical switch is about 1 to 2 nanoseconds. However, the semiconductor optical amplifier waveguide-based optical switch suffers from (a) noise, (b) polarization dependence problems, (c) wavelength dependence problems and (d) high electrical power consumption.